Further work will involve continuation of studies of percutaneous absorption of antimetabolites and their effects on stripped and normal skin. In vitro studies of penetration of human skin and hairless mouse skin will be compared in order to get some information regarding reliability of hairless mouse skin in estimating penetration through human skin. Further biopharmacological studies will be conducted with regard to triacetyl azauridine, a drug which seems to be somewhat effective in the control of psoriasis. The effects of anthralin on the cell cycle will be studied in detail because of earlier findings of interest in this regard.